path: root/includes/api/ApiMain.php

<?php

/*
 * Created on Sep 4, 2006
 *
 * API for MediaWiki 1.8+
 *
 * Copyright (C) 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * http://www.gnu.org/copyleft/gpl.html
 */

if (!defined('MEDIAWIKI')) {
	// Eclipse helper - will be ignored in production
	require_once ('ApiBase.php');
}

/**
 * @defgroup API API
 */

/**
 * This is the main API class, used for both external and internal processing.
 * When executed, it will create the requested formatter object,
 * instantiate and execute an object associated with the needed action,
 * and use formatter to print results.
 * In case of an exception, an error message will be printed using the same formatter.
 *
 * To use API from another application, run it using FauxRequest object, in which
 * case any internal exceptions will not be handled but passed up to the caller.
 * After successful execution, use getResult() for the resulting data.
 *
 * @ingroup API
 */
class ApiMain extends ApiBase {

	/**
	 * When no format parameter is given, this format will be used
	 */
	const API_DEFAULT_FORMAT = 'xmlfm';

	/**
	 * List of available modules: action name => module class
	 */
	private static $Modules = array (
		'login' => 'ApiLogin',
		'logout' => 'ApiLogout',
		'query' => 'ApiQuery',
		'expandtemplates' => 'ApiExpandTemplates',
		'parse' => 'ApiParse',
		'opensearch' => 'ApiOpenSearch',
		'feedwatchlist' => 'ApiFeedWatchlist',
		'help' => 'ApiHelp',
		'paraminfo' => 'ApiParamInfo',
	);

	private static $WriteModules = array (
		'rollback' => 'ApiRollback',
		'delete' => 'ApiDelete',
		'undelete' => 'ApiUndelete',
		'protect' => 'ApiProtect',
		'block' => 'ApiBlock',
		'unblock' => 'ApiUnblock',
		'move' => 'ApiMove',
		'edit' => 'ApiEditPage',
		'emailuser' => 'ApiEmailUser',
	);

	/**
	 * List of available formats: format name => format class
	 */
	private static $Formats = array (
		'json' => 'ApiFormatJson',
		'jsonfm' => 'ApiFormatJson',
		'php' => 'ApiFormatPhp',
		'phpfm' => 'ApiFormatPhp',
		'wddx' => 'ApiFormatWddx',
		'wddxfm' => 'ApiFormatWddx',
		'xml' => 'ApiFormatXml',
		'xmlfm' => 'ApiFormatXml',
		'yaml' => 'ApiFormatYaml',
		'yamlfm' => 'ApiFormatYaml',
		'rawfm' => 'ApiFormatJson',
		'txt' => 'ApiFormatTxt',
		'txtfm' => 'ApiFormatTxt',
		'dbg' => 'ApiFormatDbg',
		'dbgfm' => 'ApiFormatDbg'
	);

	private $mPrinter, $mModules, $mModuleNames, $mFormats, $mFormatNames;
	private $mResult, $mAction, $mShowVersions, $mEnableWrite, $mRequest, $mInternalMode, $mSquidMaxage;

	/**
	* Constructs an instance of ApiMain that utilizes the module and format specified by $request.
	*
	* @param $request object - if this is an instance of FauxRequest, errors are thrown and no printing occurs
	* @param $enableWrite bool should be set to true if the api may modify data
	*/
	public function __construct($request, $enableWrite = false) {

		$this->mInternalMode = ($request instanceof FauxRequest);

		// Special handling for the main module: $parent === $this
		parent :: __construct($this, $this->mInternalMode ? 'main_int' : 'main');

		if (!$this->mInternalMode) {

			// Impose module restrictions.
			// If the current user cannot read,
			// Remove all modules other than login
			global $wgUser;

			if( $request->getVal( 'callback' ) !== null ) {
				// JSON callback allows cross-site reads.
				// For safety, strip user credentials.
				wfDebug( "API: stripping user credentials for JSON callback\n" );
				$wgUser = new User();
			}

			if (!$wgUser->isAllowed('read')) {
				self::$Modules = array(
					'login'  => self::$Modules['login'],
					'logout' => self::$Modules['logout'],
					'help'   => self::$Modules['help'],
					);
			}
		}

		global $wgAPIModules, $wgEnableWriteAPI; // extension modules
		$this->mModules = $wgAPIModules + self :: $Modules;
		if($wgEnableWriteAPI)
			$this->mModules += self::$WriteModules;

		$this->mModuleNames = array_keys($this->mModules); // todo: optimize
		$this->mFormats = self :: $Formats;
		$this->mFormatNames = array_keys($this->mFormats); // todo: optimize

		$this->mResult = new ApiResult($this);
		$this->mShowVersions = false;
		$this->mEnableWrite = $enableWrite;

		$this->mRequest = & $request;

		$this->mSquidMaxage = -1; // flag for executeActionWithErrorHandling()
		$this->mCommit = false;
	}

	/**
	 * Return true if the API was started by other PHP code using FauxRequest
	 */
	public function isInternalMode() {
		return $this->mInternalMode;
	}

	/**
	 * Return the request object that contains client's request
	 */
	public function getRequest() {
		return $this->mRequest;
	}

	/**
	 * Get the ApiResult object asscosiated with current request
	 */
	public function getResult() {
		return $this->mResult;
	}

	/**
	 * This method will simply cause an error if the write mode was disabled
	 * or if the current user doesn't have the right to use it
	 */
	public function requestWriteMode() {
		global $wgUser;
		if (!$this->mEnableWrite)
			$this->dieUsage('Editing of this wiki through the API' .
			' is disabled. Make sure the $wgEnableWriteAPI=true; ' .
			'statement is included in the wiki\'s ' .
			'LocalSettings.php file', 'noapiwrite');
		if (!$wgUser->isAllowed('writeapi'))
			$this->dieUsage('You\'re not allowed to edit this ' .
			'wiki through the API', 'writeapidenied');
	}

	/**
	 * Set how long the response should be cached.
	 */
	public function setCacheMaxAge($maxage) {
		$this->mSquidMaxage = $maxage;
	}

	/**
	 * Create an instance of an output formatter by its name
	 */
	public function createPrinterByName($format) {
		return new $this->mFormats[$format] ($this, $format);
	}

	/**
	 * Execute api request. Any errors will be handled if the API was called by the remote client.
	 */
	public function execute() {
		$this->profileIn();
		if ($this->mInternalMode)
			$this->executeAction();
		else
			$this->executeActionWithErrorHandling();
	
		$this->profileOut();
	}

	/**
	 * Execute an action, and in case of an error, erase whatever partial results
	 * have been accumulated, and replace it with an error message and a help screen.
	 */
	protected function executeActionWithErrorHandling() {

		// In case an error occurs during data output,
		// clear the output buffer and print just the error information
		ob_start();

		try {
			$this->executeAction();
		} catch (Exception $e) {
			//
			// Handle any kind of exception by outputing properly formatted error message.
			// If this fails, an unhandled exception should be thrown so that global error
			// handler will process and log it.
			//

			$errCode = $this->substituteResultWithError($e);

			// Error results should not be cached
			$this->setCacheMaxAge(0);

			$headerStr = 'MediaWiki-API-Error: ' . $errCode;
			if ($e->getCode() === 0)
				header($headerStr, true);
			else
				header($headerStr, true, $e->getCode());

			// Reset and print just the error message
			ob_clean();

			// If the error occured during printing, do a printer->profileOut()
			$this->mPrinter->safeProfileOut();
			$this->printResult(true);
		}

		global $wgRequest;
		if($this->mSquidMaxage == -1)
		{
			# Nobody called setCacheMaxAge(), use the (s)maxage parameters
			$smaxage = $wgRequest->getVal('smaxage', 0);
			$maxage = $wgRequest->getVal('maxage', 0);
		}
		else
			$smaxage = $maxage = $this->mSquidMaxage;

		// Set the cache expiration at the last moment, as any errors may change the expiration.
		// if $this->mSquidMaxage == 0, the expiry time is set to the first second of unix epoch
		$exp = min($smaxage, $maxage);
		$expires = ($exp == 0 ? 1 : time() + $exp);
		header('Expires: ' . wfTimestamp(TS_RFC2822, $expires));
		header('Cache-Control: s-maxage=' . $smaxage . ', must-revalidate, max-age=' . $maxage);

		if($this->mPrinter->getIsHtml())
			echo wfReportTime();

		ob_end_flush();
	}

	/**
	 * Replace the result data with the information about an exception.
	 * Returns the error code
	 */
	protected function substituteResultWithError($e) {

			// Printer may not be initialized if the extractRequestParams() fails for the main module
			if (!isset ($this->mPrinter)) {
				// The printer has not been created yet. Try to manually get formatter value.
				$value = $this->getRequest()->getVal('format', self::API_DEFAULT_FORMAT);
				if (!in_array($value, $this->mFormatNames))
					$value = self::API_DEFAULT_FORMAT;

				$this->mPrinter = $this->createPrinterByName($value);
				if ($this->mPrinter->getNeedsRawData())
					$this->getResult()->setRawMode();
			}

			if ($e instanceof UsageException) {
				//
				// User entered incorrect parameters - print usage screen
				//
				$errMessage = array (
				'code' => $e->getCodeString(),
				'info' => $e->getMessage());

				// Only print the help message when this is for the developer, not runtime
				if ($this->mPrinter->getIsHtml() || $this->mAction == 'help')
					ApiResult :: setContent($errMessage, $this->makeHelpMsg());

			} else {
				global $wgShowSQLErrors, $wgShowExceptionDetails;
				//
				// Something is seriously wrong
				//
				if ( ( $e instanceof DBQueryError ) && !$wgShowSQLErrors ) {
					$info = "Database query error";
				} else {
					$info = "Exception Caught: {$e->getMessage()}";
				}

				$errMessage = array (
					'code' => 'internal_api_error_'. get_class($e),
					'info' => $info,
				);
				ApiResult :: setContent($errMessage, $wgShowExceptionDetails ? "\n\n{$e->getTraceAsString()}\n\n" : "" );				
			}

			$this->getResult()->reset();
			$this->getResult()->addValue(null, 'error', $errMessage);

		return $errMessage['code'];
	}

	/**
	 * Execute the actual module, without any error handling
	 */
	protected function executeAction() {

		$params = $this->extractRequestParams();

		$this->mShowVersions = $params['version'];
		$this->mAction = $params['action'];

		// Instantiate the module requested by the user
		$module = new $this->mModules[$this->mAction] ($this, $this->mAction);

		if( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
			// Check for maxlag
			global $wgShowHostnames;
			$maxLag = $params['maxlag'];
			list( $host, $lag ) = wfGetLB()->getMaxLag();
			if ( $lag > $maxLag ) {
				if( $wgShowHostnames ) {
					ApiBase :: dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
				} else {
					ApiBase :: dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
				}
				return;
			}
		}

		if (!$this->mInternalMode) {
			// Ignore mustBePosted() for internal calls
			if($module->mustBePosted() && !$this->mRequest->wasPosted())
				$this->dieUsage("The {$this->mAction} module requires a POST request", 'mustbeposted');

			// See if custom printer is used
			$this->mPrinter = $module->getCustomPrinter();
			if (is_null($this->mPrinter)) {
				// Create an appropriate printer
				$this->mPrinter = $this->createPrinterByName($params['format']);
			}

			if ($this->mPrinter->getNeedsRawData())
				$this->getResult()->setRawMode();
		}

		// Execute
		$module->profileIn();
		$module->execute();
		$module->profileOut();

		if (!$this->mInternalMode) {
			// Print result data
			$this->printResult(false);
		}
	}

	/**
	 * Print results using the current printer
	 */
	protected function printResult($isError) {
		$printer = $this->mPrinter;
		$printer->profileIn();

		/* If the help message is requested in the default (xmlfm) format,
		 * tell the printer not to escape ampersands so that our links do
		 * not break. */
		$printer->setUnescapeAmps ( ( $this->mAction == 'help' || $isError )
				&& $this->getParameter('format') == ApiMain::API_DEFAULT_FORMAT );

		$printer->initPrinter($isError);

		$printer->execute();
		$printer->closePrinter();
		$printer->profileOut();
	}

	/**
	 * See ApiBase for description.
	 */
	public function getAllowedParams() {
		return array (
			'format' => array (
				ApiBase :: PARAM_DFLT => ApiMain :: API_DEFAULT_FORMAT,
				ApiBase :: PARAM_TYPE => $this->mFormatNames
			),
			'action' => array (
				ApiBase :: PARAM_DFLT => 'help',
				ApiBase :: PARAM_TYPE => $this->mModuleNames
			),
			'version' => false,
			'maxlag'  => array (
				ApiBase :: PARAM_TYPE => 'integer'
			),
			'smaxage' => array (
				ApiBase :: PARAM_TYPE => 'integer',
				ApiBase :: PARAM_DFLT => 0
			),
			'maxage' => array (
				ApiBase :: PARAM_TYPE => 'integer',
				ApiBase :: PARAM_DFLT => 0
			),
		);
	}

	/**
	 * See ApiBase for description.
	 */
	public function getParamDescription() {
		return array (
			'format' => 'The format of the output',
			'action' => 'What action you would like to perform',
			'version' => 'When showing help, include version for each module',
			'maxlag' => 'Maximum lag',
			'smaxage' => 'Set the s-maxage header to this many seconds. Errors are never cached',
			'maxage' => 'Set the max-age header to this many seconds. Errors are never cached',
		);
	}

	/**
	 * See ApiBase for description.
	 */
	public function getDescription() {
		return array (
			'',
			'',
			'******************************************************************',
			'**                                                              **',
			'**  This is an auto-generated MediaWiki API documentation page  **',
			'**                                                              **',
			'**                  Documentation and Examples:                 **',
			'**               http://www.mediawiki.org/wiki/API              **',
			'**                                                              **',
			'******************************************************************',
			'',
			'Status:          All features shown on this page should be working, but the API',
			'                 is still in active development, and  may change at any time.',
			'                 Make sure to monitor our mailing list for any updates.',
			'',
			'Documentation:   http://www.mediawiki.org/wiki/API',
			'Mailing list:    http://lists.wikimedia.org/mailman/listinfo/mediawiki-api',
			'Bugs & Requests: http://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
			'',
			'',
			'',
			'',
			'',
		);
	}

	/**
	 * Returns an array of strings with credits for the API
	 */
	protected function getCredits() {
		return array(
			'API developers:',
			'    Roan Kattouw <Firstname>.<Lastname>@home.nl (lead developer Sep 2007-present)',
			'    Victor Vasiliev - vasilvv at gee mail dot com',
			'    Yuri Astrakhan <Firstname><Lastname>@gmail.com (creator, lead developer Sep 2006-Sep 2007)',
			'',
			'Please send your comments, suggestions and questions to mediawiki-api@lists.wikimedia.org',
			'or file a bug report at http://bugzilla.wikimedia.org/'
		);
	}

	/**
	 * Override the parent to generate help messages for all available modules.
	 */
	public function makeHelpMsg() {

		$this->mPrinter->setHelp();

		// Use parent to make default message for the main module
		$msg = parent :: makeHelpMsg();

		$astriks = str_repeat('*** ', 10);
		$msg .= "\n\n$astriks Modules  $astriks\n\n";
		foreach( $this->mModules as $moduleName => $unused ) {
			$module = new $this->mModules[$moduleName] ($this, $moduleName);
			$msg .= self::makeHelpMsgHeader($module, 'action');
			$msg2 = $module->makeHelpMsg();
			if ($msg2 !== false)
				$msg .= $msg2;
			$msg .= "\n";
		}

		$msg .= "\n$astriks Formats  $astriks\n\n";
		foreach( $this->mFormats as $formatName => $unused ) {
			$module = $this->createPrinterByName($formatName);
			$msg .= self::makeHelpMsgHeader($module, 'format');
			$msg2 = $module->makeHelpMsg();
			if ($msg2 !== false)
				$msg .= $msg2;
			$msg .= "\n";
		}

		$msg .= "\n*** Credits: ***\n   " . implode("\n   ", $this->getCredits()) . "\n";


		return $msg;
	}

	public static function makeHelpMsgHeader($module, $paramName) {
		$modulePrefix = $module->getModulePrefix();
		if (!empty($modulePrefix))
			$modulePrefix = "($modulePrefix) ";

		return "* $paramName={$module->getModuleName()} $modulePrefix*";
	}

	private $mIsBot = null;
	private $mIsSysop = null;
	private $mCanApiHighLimits = null;

	/**
	 * Returns true if the currently logged in user is a bot, false otherwise
	 * OBSOLETE, use canApiHighLimits() instead
	 */
	public function isBot() {
		if (!isset ($this->mIsBot)) {
			global $wgUser;
			$this->mIsBot = $wgUser->isAllowed('bot');
		}
		return $this->mIsBot;
	}

	/**
	 * Similar to isBot(), this method returns true if the logged in user is
	 * a sysop, and false if not.
	 * OBSOLETE, use canApiHighLimits() instead
	 */
	public function isSysop() {
		if (!isset ($this->mIsSysop)) {
			global $wgUser;
			$this->mIsSysop = in_array( 'sysop', $wgUser->getGroups());
		}

		return $this->mIsSysop;
	}

	/**
	 * Check whether the current user is allowed to use high limits
	 * @return bool
	 */
	public function canApiHighLimits() {
		if (!isset($this->mCanApiHighLimits)) {
			global $wgUser;
			$this->mCanApiHighLimits = $wgUser->isAllowed('apihighlimits');
		}

		return $this->mCanApiHighLimits;
	}

	/**
	 * Check whether the user wants us to show version information in the API help
	 * @return bool
	 */
	public function getShowVersions() {
		return $this->mShowVersions;
	}

	/**
	 * Returns the version information of this file, plus it includes
	 * the versions for all files that are not callable proper API modules
	 */
	public function getVersion() {
		$vers = array ();
		$vers[] = 'MediaWiki ' . SpecialVersion::getVersion();
		$vers[] = __CLASS__ . ': $Id: ApiMain.php 37349 2008-07-08 20:53:41Z catrope $';
		$vers[] = ApiBase :: getBaseVersion();
		$vers[] = ApiFormatBase :: getBaseVersion();
		$vers[] = ApiQueryBase :: getBaseVersion();
		$vers[] = ApiFormatFeedWrapper :: getVersion(); // not accessible with format=xxx
		return $vers;
	}

	/**
	 * Add or overwrite a module in this ApiMain instance. Intended for use by extending
	 * classes who wish to add their own modules to their lexicon or override the
	 * behavior of inherent ones.
	 *
	 * @access protected
	 * @param $mdlName String The identifier for this module.
	 * @param $mdlClass String The class where this module is implemented.
	 */
	protected function addModule( $mdlName, $mdlClass ) {
		$this->mModules[$mdlName] = $mdlClass;
	}

	/**
	 * Add or overwrite an output format for this ApiMain. Intended for use by extending
	 * classes who wish to add to or modify current formatters.
	 *
	 * @access protected
	 * @param $fmtName The identifier for this format.
	 * @param $fmtClass The class implementing this format.
	 */
	protected function addFormat( $fmtName, $fmtClass ) {
		$this->mFormats[$fmtName] = $fmtClass;
	}

	/**
	 * Get the array mapping module names to class names
	 */
	function getModules() {
		return $this->mModules;
	}
}

/**
 * This exception will be thrown when dieUsage is called to stop module execution.
 * The exception handling code will print a help screen explaining how this API may be used.
 *
 * @ingroup API
 */
class UsageException extends Exception {

	private $mCodestr;

	public function __construct($message, $codestr, $code = 0) {
		parent :: __construct($message, $code);
		$this->mCodestr = $codestr;
	}
	public function getCodeString() {
		return $this->mCodestr;
	}
	public function __toString() {
		return "{$this->getCodeString()}: {$this->getMessage()}";
	}
}